For effective treatment of a septicemia or bacteremia suspected patient, blood culture testing is performed to accurately diagnose what causative organism is responsible for septicemia and what therapeutic agent is effective against the causative organism. Generally, the blood culture testing is performed by the following procedure. First, blood is aseptically collected from the patient. For the blood collection, a suitable tool such as a syringe is used to keep the skin from being contaminated by microbes normally present on the skin and microbes present in ambient environments. The blood samples are mixed with liquid blood culture media and observed whether microorganisms grow during culture at 37° C., typically for 1-2 days. The media inoculated with the blood are separately cultured under aerobic and anaerobic conditions. As a result, anaerobic microbes (incapable of growing in the presence of oxygen) as well as aerobic microbes (capable of growing in the presence of oxygen) or facultative anaerobic microbes (capable of growing with or without oxygen) can be cultured in the media. The bottoms of culture bottles containing the media are usually coated with chemicals that tend to discolor or emit fluorescence when microorganisms grow. Thus, the use of blood culture systems capable of recognizing color changes or fluorescence enables automatic detection of the growth of microorganisms in the media. After the microorganisms are extracted from the patient and cultured until the number of the microorganisms reaches an optimum level (105 cell/ml), subsequent processes (such as identification of the pathogenic strain and antibiotic susceptibility testing) are performed. At this time, pure culture is required for selectively isolating the pathogenic strain from the blood culture solutions and culturing the pathogenic strain. According to a general pure culture method, the culture solutions (containing the microorganisms) after blood culture are plated on agar media to obtain a necessary amount of the microbe. At this time, it takes about 16 to 24 hours for the microbe to form colonies. The conventional pure culture method requires a relatively long time, which remarkably deteriorates the therapeutic effect on bacterial septicemia. Therefore, a shorter culture time is required for more rapid antibiotic susceptibility testing.
The conventional method also requires a process for isolating microorganisms from foods or natural environments to identify and culture the microorganisms. However, microorganisms present in very small quantities in such environments are not easy to isolate. Even when microorganisms are present in relatively large quantities, a time-consuming process for culturing the microorganisms is necessary to isolate the microorganisms.
Therefore, there is a need for a method of isolating microorganisms from various environments, for example, tissues, blood, feces, and urine derived from organisms, foods, and natural environments, in an effective and time-consuming manner.